If you mean -370º C, the answer is no planet at all.
There is no such temperature in the Universe.
In case of -370º F [-223º C], the answer is Pluto (but it is now considered a dwarf planet).
Neptune and Uranus have a lower temperature than -370º F in the atmospheric tropopause (jovian planets have to solid surface).
Curiously, Neptune higher layers of the atmosphere are less cold that in lower troposphere, due to the high concentration of methane in upper atmosphere).
Other solar system bodies (like Triton moon) have even lower temperatures, but they are not planets.
Chat with our AI personalities
Neptune is the planet with an average temperature of about -400°F (-240°C) in its upper atmosphere, making it the coldest planet in our solar system. This extreme cold is due to Neptune's distance from the Sun and its composition of mainly hydrogen, helium, and methane gases.
Venus has an average surface temperature of about 465 degrees Celsius (869 degrees Fahrenheit), making it the hottest planet in our solar system due to its thick atmosphere made up mainly of carbon dioxide.
the temperature of a UV light is 10nm-400 degrees fahrenheit
The surface of Pluto, in comparison, can range from a low temperature of 33 Kelvin (-240 degrees Celsius or -400 degrees Fahrenheit) and 55 Kelvin (-218 degrees Celsius or -360 degrees Fahrenheit). The average surface temperature on Pluto is 44 Kelvin (-229 Celsius or -380 Fahrenheit).
The temperature on Pluto is about as cold as physically possible. The planet receives almost no heat from the Sun, so most of its atmosphere is perpetually frozen. It also has no discernible internal heat. Scientists using the Submillimeter Array have discovered that Pluto's maximum temperature is about 43 K (−230 °C), 10 K colder than expected.
the temperature and heat - wikigirl